What to do about this affiliate

Someone became an affiliate for my physical product but they are writing what I would consider to be borderline negative things about my company/product which is really confusing, because they also write a lot of positive things as well, but they put more emphasis on the negatives - most of which wouldn't apply to a regular customer.
they want to make money off promoting my products right?

The first thing they did was buy a bunch of our products using their affiliate link (I have no problem with this) and then they used a 40% off coupon on top of it for black friday. Our website had a glitch that happened during the sale (this was a fluke) so they got free shipping. We resolved to ship the product very cheaply for them so they would not have to pay shipping since the mistake was on our end, but it would take longer to receive it. We lost money because of the affiliate+coupon+shipping (affiliate is 20%, and shipping cost about 30% of the product cost). When the person got their product they then wrote a blog post about it - praising the product but they spent the majority of the post on how much they hated the shipping method we used and how it took too long to receive the product (they don't mention the customer service on our end and the free shipping part). They then promoted the blog post with tweets.

Since then they've been very vocal about our products on their blog and on twitter. They love the product, but some of the tweets are a little negative like "my boyfriend lost this one part to (product) - I hate how they make the part so small" (the part size is unavoidable and it isn't made to be taken apart so I'm not sure what they're doing).

and then "two days later, still looking for the part from (product)" or "I got weird looks for giving (product) to a friend for christmas"
Usually the tweets contain a link to their web review or video they made with affiliate links.
The videos that have made of the product are strange - one of them is just them holding a camera over the directions zoomed in - no sound or anything. Other videos are blurry of the product zoomed in - no sound.

I'm not entirely sure why they would be slightly negative about the product that they are trying to make money off of, or make these strange videos that don't really serve any purpose.
They have other affiliate links on their site too.
They haven't made any affiliate sales aside from purchasing products with their own link twice.

Should I say anything to them or let this go and let them continue? They are really active on twitter, though who knows who is paying attention. It's just feeling a little creepy/strange to me. Then again if I speak to them who knows what they'll write about the company....